Life In Slow Motion

Can hanging upside down from a branch, hardly moving for up to 18 hours a day, help an animal survive? In the case of a three-toed sloth - yes !

This strange and appealing animal, one of the most common larger mammals in New World rainforests, has a lifestyle that is unusual but that suits it perfectly for life in the canopy. It's way of surviving is based on using as little energy as possible. That means it doesn't need to eat as much, and it can live on leaves, which are not very nutritious.

Sloths spend mos of their time upside-down, hanging from branches by their three-inch-long claws. They even sleep and have babies in this position. Sloths eat the leaves of around fifteen to thirty different kinds of trees. But they spend most of their time in the branes of a few favorites.

Leaves are hard to digest, so sloths have special large stomachs. Their digestion takes place at the same pace as the rest of their lives - very slowly. Food can take up to a month to pass through a sloth's digestive system.

This is a long time, and leaves don't supply much energy. So sloths live in ways that use up as little energy as possible. Moving little and slowly is one way to save energy. They also burn their food at a very slow rate. And they don't keep their body temperatures as constant as most other mammals (to do so takes a lot of enery). Sloths use their surrounding to adjust their body temperatures.

Because of this, a sloth that needs to warm up after a chilly night must climb to a patch of sunlight in the upper canopy.

This warms it up, but also puts it in danger. Out in the open, a sloth has no protection. If a hungry eagle spots it, it cannot run.

The rest of the time though, down in its usual spots among the leaves, the sloth is pretty safe. It has tiny plants growing in the grooves of its hair. These plants make its hair look greenish. This color, and its very slow movements, make the sloth very hard to spot among the leaves. It tends to look more like a bunch of epiphytes than like an animal.

And in fact, for many insects, a sloth is home. Over 900 beetles have been found on a single sloth...and other creatures like mites and other insects also live in its fur.

A few years ago, scientists at the Smithsonian Tropical Research Institute in Panama found that on of these insects, a kind of moth, not only lives on the sloth but depends on it to feed its developing young. Here is how it happens.

About once every two weeks, a three-toed sloth makes a very, very slow trip all the way down to the ground. Here it digs a hole and deposits its droppings in the hole.

At this point the moths that livein the sloth's fur fly out and lay their eggs in the droppings. The droppings will be food for the moth's developing offspring.